1. Field of the Invention
The present invention relates to an electronic equipment including a first casing provided with a circuit board on which is mounted a heat-emitting element and a heat-discharging sheet that discharges heat from this element, and a second casing accommodating a display device and that is rotatably mounted on the first casing, and more particularly relates to an electronic equipment provided with a cooling structure.
2. Description of the Related Art
As disclosed in Japanese Patent Unexamined Publication No. 7-142886 and Japanese Patent Unexamined Publication No. 8-162576, in examples of the related art in the above technical field, heat is transported from a first casing mounting a heat-emitting element to a second casing accommodating a display device etc. and is discharged from the walls of the second casing.
In Japanese Patent Unexamined Publication No. 7-142886 (Prior art 1), a heat-discharging member mounted on a heat-emitting element accommodated in a casing, and a heat-discharging member provided in a second casing that accommodates a display device etc. are connected by a flexible tube and the heat-emitting element is cooled by driving cooling liquid between the respective heat-discharging members.
On the other hand Japanese Patent Unexamined Publication No. 8-162576 (Prior art 2) discloses a technique in which a hinge that connects a first casing mounting a heat-emitting element and a second casing accommodating a display device etc. is formed of material having high thermal conductivity and a heat-discharging member mounted on a heat-emitting element and a heat-discharging member provided in the second casing and the hinge are thermally connected by means of a high conductivity member, thereby allowing heat transfer to be performed to the second casing so as to increase the area from which the heat from the heat-emitting elements can be discharged.
Currently, in electronic equipments such as portable personal computers, with increased heat emission of the elements due to upgrading of performance, together with advances in reduction in casing thickness and weight and since these electronic equipments are usually battery-driven, it has become necessary to achieve reductions in power consumption of the equipment as a whole.
In Prior art 1, motive power is required in order to drive the liquid. The problem was therefore not considered that this would lead to increased power consumption for the liquid drive and increased weight for the liquid drive device, which result in disadvantages from the point of view of portability. In contrast, prior art 2 was applicable only to a specific heat-emitting element, and if a plurality of heat-emitting elements were to be cooled, a heat path to the hinge had to be provided in respect of each heat-emitting element. Furthermore, in order to decrease the thermal resistance from the heat-emitting element to the hinge, it was necessary to arrange the heat-emitting element and hinge adjacent each other. That is, it was not taken into consideration that an obstacle to obtaining higher performance of the system as a whole was presented by the restrictions in layout on the wiring board of the heat-emitting element due to considerations regarding space for the heat path and distance to the hinge, in order to suppress temperature rise of all the heat-emitting elements and also to suppress temperature rise of casing surfaces such as the keyboard.
Also, in the case of electronic equipments for which portable use is a presupposition, it is necessary not only that the temperature of the keyboard mounted on the casing should be in a suitable range, but also that of device surfaces of the casing that come into frequent direct contact with the user (for example when the equipment is used resting on the knees or legs etc.). However, the problem was not considered that, with increase in the amount of heat resulting from upgraded performance of the elements, rise in temperature occurs of the casing in the vicinity of the location where the elements are mounted, the keyboard mounted on the casing and/or the back surface of the display device whereby heat is transmitted as in the case of prior art 2, giving rise to discomfort of the user. In other words, it was not taken into consideration appropriate distribution of the heat generated to the equipment is needed when the amount of heat generated within the casing increased, in order to guarantee performance by cooling the elements and to keep the temperature of the casing and/or keyboard in a range comfortable for the user during operation.
Furthermore, due to reasons of cost of components and improvement of performance in the case of maintenance or repair etc., in such portable electronic equipment, the system specification may be altered and, accompanying this, the layout of the elements and/or equipment within the casing is often altered; when this is done, the problem arises that large alterations have to be made to the cooling structure, so that production cost is raised and furthermore improved performance is prevented if a sufficient cooling performance cannot be ensured. In particular, consideration was not given to the problem that, in the case of a liquid crystal device typically employed in a display device mounted on a second casing, there are restrictions on the temperature of the device in order to ensure proper display performance, so that proper display performance cannot be achieved unless the amount of heat transmitted to the second casing is regulated such that, in coping with alterations and performance upgrades of the system specification, the upper limit of the display temperature is not exceeded.
An object of the present invention is to provide an electronic equipment having a cooling structure suited to small-thickness light-weight casings whereby rise in temperature of the surface of the casing accommodating a heat-emitting element and a keyboard etc. can be suppressed and the temperature of the heat-emitting element can be cooled to a predetermined temperature, with no discomfort to the operator, irrespective of the layout on the wiring board of the heat-emitting element and/or the layout of equipment items within the casing.
A further object of the present invention is to provide an electronic equipment having a cooling structure capable of maintaining the casing and keyboard at a temperature at which there is no discomfort to the operator whilst the heat-emitting element is maintained below a predetermined temperature and the amount of heat generated from the heat-emitting element and/or device within the casing is suitably dispersed in the entire equipment.
Yet a further object is to provide an electronic equipment having a cooling structure whereby the amount of heat emitted from the casing can be regulated to cope with changes in the layout of heat-emitting elements and/or equipment within the casing.
In order to solve the above problems, an electronic equipment according to the present application comprises a first casing on which are mounted a keyboard and a wiring board, and a second casing accommodating a display device and rotatably mounted on the first casing by means of a hinge, and further comprises a first heat-discharging member thermally connected with one or more elements that are the subject of cooling arranged within the first casing and the surface of the first casing, a second heat-discharging member arranged within the second casing, and means for connection that thermally connects the first and the second heat-discharging members. Further, there is provided a construction comprising a flexible thermally conductive member provided between the element that is the subject of cooling and the first heat-discharging member. Also, there is provided a construction comprising a heat-discharging member arranged between a plurality of or a single one of the elements that are the subject of cooling and the keyboard and thermally contacting the elements that are the subject of cooling and the keyboard.
Also, a construction may be provided in which an electronic equipment comprises a first casing on which are mounted a keyboard and a wiring board, and a second casing accommodating a display device and rotatably mounted on the first casing by means of a hinge, and further comprising a thermally conductive member thermally connected with one or more elements that are the subject of cooling arranged within the first casing and the surface of said first casing, and connection means for thermally connecting the first casing and second casing.
Further, the connection means may comprise a thermally conductive member connected by contacting the first heat-discharging member and the second heat-discharging member and further comprise a thermally conductive member comprising one or other of a thermally conductive member connected to the first heat-discharging member and a thermally conductive member connected to the second heat-discharging member and connected in contact with these thermally conductive members or heat-discharging member.
Furthermore the size of the region of contact of the means for contact may be adjustable.
The first heat-discharging member receives the heat of a plurality of heat-emitting elements on the wiring board and part of this is discharged from the surface of the first casing through a heat-discharging path provided by thermal connection between the first heat-discharging member and the surface of the casing to the atmosphere. The rest of the heat is thermally conducted to the second heat-discharging member through the connection of the first heat-discharging member and second heat-discharging member and is discharged to the atmosphere from the surface of the second casing. At this time, the first heat-discharging member receives the heat of the plurality of elements concurrently, so the heat of the plurality of elements that are thermally connected to the first heat-discharging member is discharged from the surface of the first casing and the surface of the second casing irrespective of their layout on the wiring board. A layout of the elements such as to achieve high performance of the system can therefore be achieved without lowering the cooling performance of the heat-emitting elements on the wiring board and large-scale alterations to the cooling structure are not necessary even if the heat-emitting elements and/or wiring board are altered due to alteration of the specification of the system.
Also, the heat generated from heat-emitting elements and/or device within the first casing is discharged to the outside from the first heat-discharging member by being transmitted to the first casing or the keyboard. Concurrently, it is discharged to the outside from the second casing, which is thermally connected to this first heat-discharging member. That is, since the heat generated in the interior of the casing is distributed to all the surfaces before being discharged to the outside, the casing where it is touched by persons is appropriately cooled at the same time as cooling of the elements, without either local rise in temperature of the surface of the casing or rise in temperature to the point of causing discomfort to the user.